Does Lady Eliza or Belthir appear in the main quests, since they weren't in Labyrinth of Ruin?
I'm really disapointed about this, but only the new lieutenants appears on SoN. So, no Farrow members, no Splig, no Belthir, only Rylan and Thystaine Olliven, Verminous and Gargan Mirklace. That's really bad
Actually this is good.
If you buy the Lieutenant packs of your favorite Lieutenants then you can use them as Agents in any of the new quests offered by Shadows Of Nerekhall by swapping them with an open monster group.
Many of the Agents cannot be played in a quest and sometimes a whole campaign that normally features them. And Visa-versa you can use the Lieutenants from Shadows of Nerekrall in the other campaigns to add new spice and story elements to older quests that you many or may not have already played. The Plot cards, threat and fortune add great flavor to the game too.
And you can always use the Quest Vault to design your own quest to slip into Shadows campaign using Lieutenants and items from the other expansions.
FFG are producing a great 'sandbox' product that scratches the itch that conventional RPG's don't scratch.